SciELO - Scientific Electronic Library Online

 
vol.18 número4Decay resistance, thermal degradation, tensile and flexural properties of sisal carbon hybrid compositesEffect of weathering on physical and mechanical properties of hybrid nanocomposite based on polyethylene, woodflour and nanoclay índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Revista

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • No hay articulos similaresSimilares en SciELO
  • En proceso de indezaciónSimilares en Google

Compartir


Maderas. Ciencia y tecnología

versión On-line ISSN 0718-221X

Maderas, Cienc. tecnol. vol.18 no.4 Concepción  2016

http://dx.doi.org/10.4067/S0718-221X2016005000053 

ARTÍCULO

CO2 adsorption on agricultural biomass combustion ashes

Sebastián Lira-Zúñiga1,♠, César Sáez-Navarrete1, Leonardo Rodríguez-Córdova1, Leandro Herrera-Zeppelin2, Ronaldo Herrera-Urbina3


1Departamento de Ingeniería Química y Bioprocesos, Pontificia Universidad Católica de Chile, Santiago. Chile.
2Departamento de Ingeniería Química y Biotecnología, Universidad de Chile, Santiago. Chile.

3Departamento de Ingeniería Química y Metalúrgica, Universidad de Sonora, México.

Corresponding author


ABSTRACT

Carbon capture and storage has become an alternative means of confronting global warming. Further research and development into adequate and low-cost materials is required for CO2 adsorption technologies.

Samples of fly ash, bottom ash and their respective pellets, produced from wheat bran combustion, were characterized and tested to assess their capacity for CO2 adsorption at different temperatures. Neither the ashes nor their pellets were subject to prior thermochemical activation.

The bottom ash sample and its pellets showed a higher adsorption capacity for the majority of the temperatures studied. The pelletized bottom ash reached the maximum adsorption capacity (0,07 mmol CO2/g), followed by the non-pelletized bottom ash (0,06 mmol CO2/g); both at an adsorption temperature of 25°C.

CO2 adsorption of bottom ash, from the combustion of wheat bran (agricultural biomass), by a physical adsorption mechanism was demonstrated whereas with the fly ash sample, CO2 adsorption by both physical and chemical adsorption mechanisms was identified.

Keywords: Bottom ash, CO2 capture, fly ash, pellet, wheat bran.


INTRODUCTION

The reduction of CO2 emissions in order to stabilize global warming has become a contemporary challenge (Hoyos Barreto et al. 2008, Da Gama et al. 2010, Wilcox 2012). Nowadays, research into Carbon Capture and Storage (CCS) technologies is a topic of worldwide interest, as it can be used to capture CO2 emissions from fossil fuel power plants.

The main carbon capture technologies are based on systems of absorption, adsorption and on membrane separation and cryogenic distillation technologies. The process based on adsorption phenomena is considered to be one of the most promising technologies in terms of capturing CO2 from combustion gases (Arenillas et al. 2005), giving rise to the possibility of an efficient separation in diluted gas mixtures (Wilcox 2012). Within this context, it is important to note the study of new low-cost adsorbents (Boumediene et al. 2015) which may hold significant CO2 adsorption capacities.

Combustion coal and agricultural biomass ashes provide a viable alternative, are low-cost and have the potential to capture the CO2 produced by combustion gases because of these byproducts contain significant amount of reactive metal oxides (Wilcox 2012).

The ashes produced from coal combustion are chemically heterogeneous amorphous solids. Their physicochemical properties depend on the conditions of the combustion process itself and the type of fuel being used (Amaya 2006). Ashes are common industrial-sourced alkaline byproduct (Gerdemann et al. 2007, Wilcox 2012). They contain about 90% and 99% inorganic compounds and between 1% and 9% organic compounds (Vassilev 2005). The main inorganic substances of coal combustion ashes are silicon dioxide (SiO2), calcium oxide (CaO), iron oxide (Fe2O3), magnesium oxide (MgO) and aluminium oxide (Al2O3) (Hong et al. 2009, Malik and Thapliyal 2009, Wilcox 2012). Agricultural biomass combustion ashes have not been thoroughly characterized, even though they may represent a viable alternative for CCS applications.

In 2012 the United States produced approximately 52,1 million tonnes of fly ash, 14,1 million tonnes of bottom ash and 1,7 million tonnes of slag (ACAA 2012) in coal-based energy generation alone. In 2007, Eastern Europe produced 4,6 million tonnes of coal fly ash 5,7 million tonnes of coal bottom ash and 1,5 million tonnes of boiler slag (ECOBA 2007). As a consequence of the increased amount of ash generated over the last few decades (ACAA 2012), the search for new alternatives of energy recovery has widened.

Moreover, new alternatives biomass fuels are widely used in combustion processes and biomass ashes generated are becoming a burgeoning problem (Torres-Fuchslocher and Varas-Concha 2015). This search is aimed at reducing the environmental impacts that stem from the inappropriate management of these waste materials (Arenillas et al. 2005, Maroto-Valer et al. 2005, Hong et al. 2009, Ríos et al. 2009, Lopez-Anton et al. 2011).

In this research work, two types of ash samples from the combustion of agricultural biomass (wheat bran), in powder and pellet forms, were characterized and tested as CO2 adsorbents. The ash samples tested were the following: fly ash (FA), pelletized fly ash (PFA), bottom ash (BA) and pelletized bottom ash (PBA). Their CO2 adsorption capacity and degree of reversibility were evaluated, and their physicochemical characterization enabled identification of the main CO2 adsorption mechanisms.


MATERIALS AND METHODS

Fly ash (FA), bottom ash (BA) and their respective pellets were studied (PFA and PBA). FA and BA samples of wheat bran combustion were obtained through an industrial biomass boiler (4000 kcal/h). Pellets measuring 5mm in diameter were prepared at 200 psi for all samples (Napoli NP-RD10A). The samples tested were not subject to chemical or thermal activation.

The relative constituent oxides of the two ash samples were used to calculate their corresponding chemical composition.

The specific surface area of the two types of ash and their respective pellets was determined from nitrogen adsorption isotherms at -196°C, using an ASAP 2010 Micrometrics sorptometer.

The BET method (Brunauer et al. 1938) was used to calculate the specific surface area (SBET). Using data from the BET isotherm, both the pore and micropore volumes were established. The pore volume ranging from 1,7 nm to 300 nm was determined by using the BJH method (Barrett et al. 1951). The micropore volume, on the other hand, was calculated using the t-plot method. By taking both the specific surface area and the pore volume into account, the average pore size was calculated using the equation 4Vtotal/SBET.

CO2 adsorption mechanisms on FA and BA were identified using data from the N2 adsorption isotherm at -196°C. Additionally, the research demonstrated whether or not these mechanisms were modified by the pelletization process of both samples (PFA and PBA).

The general morphology and porous structure of the ash samples and their pellets were characterized by means of scanning electron microscopy SEM (LEO VP 1400).

The adsorption capacity of the ashes and their pellets at different temperatures (25°C, 40°C, 60°C, 80°C and 100°C) was investigated using a TG Q500 thermogravimetric analyzer (TGA), with a sample capacity of 20-25 mg.

To determine the initial conditions for the adsorption capacity of the ashes, a flow of N2 (100% w/w) was introduced at a rate of 100 mL/min and at a temperature of 100°C for 30 minutes. This was subsequently adjusted to the required adsorption temperature, prior to the introduction of a CO2 flow (at 100% w/w concentration) at a rate of 100 mL/min. After adsorption, a new flow of N2 at a rate of 100 mL/min was again introduced to initiate desorption of the sample at the same temperature. The adsorption capacity was calculated from the results of gravimetric analyses.


RESULTS AND DISCUSSION

Table 1 shows the main alkaline oxides (K2O; CaO; MgO; SiO2; Na2O; Al2O3; Fe2O3 and MnO) of the ash samples studied. Also shows significant differences can be seen between the amount of the principal metal oxides present in FA and BA samples. In addition, this table shows the notable presence of volatile components (LOI, Loss on Ignition).

Table 1. Main components of FA and BA ash samples.

 

The texture characterization results (Table 2), show that the BA sample presents greater specific surface area than the FA. It can be noted that the pelletization process reduces the specific surface area of both samples, to 34% for the FA and to 58,3% for the BA.



Table 2. Texture properties of ash and pellet samples determined from N2 adsorption isotherms.


 

By comparing the specific surface area of these ash samples with commercial adsorbents, activated carbon with large pores was found to have a specific surface area in the range of 200-600 m2/g (Wilcox 2012), a value significantly higher than the samples studied here. However, there are commercial adsorbents with similar specific surface areas to the mesoporous activated carbon, with values ranging from 10-100 m2/g (Sanz 2012), as well as resins, which have specific surface areas between 15 and 120 m2/g (Wilcox 2012). Such values coincide with the lower range of the specific surface area of both the aforementioned commercial adsorbents.

The microporosity per unit of the pore volume ratio means that the BA consists of 22% micropores, the PBA 17%, the FA 3,5% and the PFA 1,5%. Therefore, the specific surface area of the BA was composed of 2,64 m2/g micropores and 9,36 m2/g mesopores. The PBA contained 1,19 m2/g of micropores and 5,81 m2/g of mesopores. The specific surface area of the FA was composed of 0,18 m2/g micropores and 4,83 m2/g mesopores, while the PFA was 0,03 m2/g micropores and 1,70 m2/g mesopores. These results provide evidence of a greater presence of micropores in the BA and PBA samples.

Table 2 also shows that the pore size was not affected by the samples undergoing pelletization. For the large-pore activated carbon, the resins, the activated alumina (Wilcox 2012), the mesocarbon and the graphene (Chen-Hsiu 2012), a pore size similar to the ash samples and their respective pellets was documented.

According to the pore size result, all the FA, BA, PFA and PBA are mesoporous solids, given that their registered pore sizes ranged from between 2 nm and 50 nm. All the samples studied fell into the lower range of pore size according to IUPAC (International Union of Pure and Applied Chemistry) classification (Table 2). It is important to note that the kinetic diameter of CO2 (0,33 nm) is smaller than the diameter of FA, PFA, BA and PBA pores.

The kinetic diameter of CO2 is similar to most of the gas species present in the gas mixture of interest (typical gas-mixture components include N2, O2 and CH4), and consequently CO2 tends to be more reactive than these species due to its stronger quadrupole moment, making it an easier target for selective capture (Wilcox 2012).

Given the pore size, the predominant mechanism of internal transport for the FA, BA, PFA and PBA was the Knudsen diffusion. This is instead of free molecular diffusion and surface diffusion, in which the free motion of the molecules in the gaseous phase is greater than the pore diameter. Here, conditions can lead to molecules colliding with the internal pore walls rather than collisions occurring between the gas molecules. This type of internal diffusion mechanism is typical of mesoporous and microporous solids (Castañeda 2012).

The porous structure highlighted by SEM analysis shows that the FA (Figure 1) and the BA (Figure 3) can be considered amorphous and heterogeneous solids. The SEM analysis shows changes to the structure of the PFA pellet (Figure 2) compared to the FA, and likewise the PBA pellet (Figure 4) compared to the BA. Nevertheless, they retain their amorphous and heterogeneous solid condition.

Figure 1. SEM image of FA sample (3KX).

Figure 2. SEM image of PFA sample (3KX).



Figure 3. SEM image of BA sample (3KX).

Figure 4. SEM image of PBA sample (3KX).

 

According to IUPAC classification, the N2 adsorption isotherm at -196°C for the BA and PBA samples, corresponds to isotherm type IV (Figure 5). This type of isotherm is common in mesoporous solids, in which multilayer physical adsorption mechanisms predominate. The type 4 isotherm is similar in form to that of type II at low pressures. A distinctive feature of this type of isotherm is its hysteresis loop. The isotherm for the FA and PFA samples corresponds to a type II isotherm (Figure 6). This type of isotherm is present in macroporous solids in which multilayer adsorption mechanisms predominate.

Figure 5 indicates that the volume of adsorbed N2 on the BA sample is greater than that of the PBA sample. In addition, the BA and PBA isotherms show a hysteresis loop under medium relative pressures (p/p0 =0,45). This confirms the presence of mesopores in both ash types.

Both the BA and PBA samples showed a rapid increase of nitrogen adsorption under very low relative pressures (p/p0 < 0,01). This process is typical of molecular-sized pores and indicates the existence of micropores. This latter point confirms, once more, the presence of micropores in both samples.

In the region of relative pressures, between p/p0 = 0,01-0,45 the amount of adsorbed nitrogen on the BA and PBA samples (Figure 5) and the FA sample (Figure 6), increases slowly and progressively. This type of surface adsorption process indicates a monolayer formation.

In the region of elevated relative pressures (p/p0 > 0,45) the BA and PBA isotherms are characterized by the presence of hysteresis loop. The hysteresis loop arises because of the process whereby the mesopores in these samples are filled. This is controlled by the phenomenon of capillary condensation (an irregular size of capillaries) as well as by the percolation properties of the solid.




Figure 5. N2 adsorption isotherm at -196 °C for BA and PBA.


Figure 6. N2 adsorption isotherm at -196 °C for FA and PFA.

 

The adsorption capacity of the four different samples of wheat bran ash tested in this research is presented in Figures 7 and 8 at five different temperatures. In powder form, the BA sample exhibits the greatest CO2 adsorption capacity at an adsorption temperature of 25°C, reaching 0,06 mmol of CO2/g (Figure 7), whereas the FA sample displays the greatest CO2 adsorption capacity at the adsorption temperature of 100°C, capturing 0,024 mmol of CO2/g (Figure 8). Furthermore, the BA sample exhibits a greater CO2 adsorption capacity in the majority of the adsorption temperatures investigated. Only at a temperature of 100°C did the FA display a greater capacity than the BA.


Figure 7. CO2 adsorption capacity of BA and PBA at different temperatures.




Figure 8. CO2 adsorption capacity of FA and PFA at different temperatures.

 

Figure 7 also shows that the CO2 adsorption capacity of the BA decreased when the adsorption temperature was increased. Therefore, this confirms that the dominant adsorption mechanism in the BA sample was one of physical adsorption (Maroto-Valer et al. 2005). In relation to FA, Figure 8 shows that an increment in temperature increases CO2 adsorption capacity, suggesting that not only physical adsorption but also chemical adsorption could be occurring (Maroto-Valer et al. 2005). Alkaline metal oxide (such as K2O) might react with CO2 and produce K2CO3 at higher temperatures (Yong et al. 2002). It is probable that the existence of some kind of alkaline functional group on the surface, such as the K2O corresponding to the FA, could explain the increased CO2 adsorption capacity when the adsorption temperature is raised. This could be confirmed by research with amine impregnated adsorbent (polyethylenimine or PEI). This would indicate whether, by raising the adsorption temperature from 25°C to 75°C, it would be possible to increase CO2 adsorption capacity (Chen-Hsiu 2012). When an adsorbent presents alkaline compounds on the surface, a part of this material is accumulated inside the pore at low temperatures, limiting the CO2 diffusion process. At high temperatures, the alkaline functional groups may not accumulate in the pores, allowing for a high diffusion rate of CO2. This increases the reaction rate of CO2 with the alkaline compounds distributed into the interior of the pores, resulting in an increase of the CO2 adsorption capacity (Sayari 2010).

Regarding the pellets, the adsorption capacity decreased in the PFA compared to that of the FA. In addition, it behaved differently to the FA following the increase of the adsorption temperature. The pelletization of the FA seems to have changed the structure of the pores, which affected access to the active adsorption sites and, therefore, its CO2 adsorption capacity.

Just as with the BA, the PBA registered a decrease in its CO2 adsorption capacity following the increase of the adsorption temperature. However, in contrast to the FA, the CO2 adsorption capacity of the PBA rose slightly compared to that of the BA. The decrease in adsorption capacity following a temperature increase corresponds to a classic physical adsorption mechanism. Here, an increase in temperature disturbs the surface stability of the CO2 molecule, causing its liberation by increasing surface adsorption energy and the molecular diffusion rate (Maroto-Valer et al. 2005). Adsorbents like zeolites, activated carbons (Xu et al. 2002) and anthracites (Maroto-Valer et al. 2005) have also demonstrated such behaviour.

The maximum CO2 adsorption capacities registered by the BA and PBA are comparable (0,06 and 0,07 mmol of CO2/g respectively) with that of other solids at the adsorption temperature of 25°C. Both samples exhibit an adsorption capacity of 0,09 mmol of CO2/g (Arenillas et al. 2005), similar to that of raw coal. Furthermore, this is greater than the adsorption capacity of commercial adsorbents like mesoporous silica (MCM-41), which can reach a capacity of 0,04 mmol of CO2/g (Yue et al. 2006). Activated carbon has an adsorption capacity of 1,66 mmol CO2/g (Pevida et al. 2008), which is substantially higher than that of the samples studied in this research work. Given that they require no activation, unlike other commercial absorbents, the BA and PBA could have future potential as low- cost adsorbents.

The adsorption capacity of fly ash with a high content of partially combusted coal has generated values between 0,39 and 0,915 mmol CO2/g (Maroto-Valer et al. 2008) at an adsorption temperature of 30°C. These are higher than the BA and PBA values, given the high content of uncombusted carbon in the latter.

As mentioned previously, BA (12 m2/g) and PBA (7 m2/g) have small specific surface areas compared to certain commercial adsorbents. Solids such as anthracite, with a small specific surface area and high CO2 adsorption capacity, present a specific surface area of 1,34 m2/g and an adsorption capacity of 0,868 mmol of CO2/g (Maroto-Valer et al. 2008).

CONCLUSIONS

Fly ash and bottom ash samples produced by an industrial process of wheat bran agricultural biomass combustion, in unprocessed powder and pelletized forms, have been physically and chemically characterized.

The study of N2 adsorption at -196°C has shown that the BA and PBA samples are mainly composed of mesoporous solids (with pores sizes of 2-50 nm), while the FA and PFA samples are primarily macroporous solids (with pores greater than 50 nm).

The BA presented the largest specific surface area (12 m2/g), followed by the PBA pelletized form (7 m2/g).

CO2 adsorption on BA involves a physical adsorption mechanism, given that its CO2 adsorption capacity decreased following an increase of the adsorption temperature. This mechanism was also displayed by the PBA sample. On the other hand, the FA samples showed the presence of both physical and chemical adsorption mechanisms. As a result of the pelletization process, the CO2 adsorption capacity of the PFA sample was reduced significantly.

The greatest CO2 adsorption capacity was obtained with the PBA sample, reaching 0,07 mmol of CO2/g at 25 °C. A similar CO2 adsorption capacity was obtained by the BA at 25°C (0,06 mmol of CO2/g).

The PBA pelletized form of the bottom ash from the wheat bran agricultural biomass combustion therefore showed characteristics which could result in its use as an efficient and low-cost adsorbent for the capture of CO2.


ACKNOWLEDGMENTS

The authors wish to express their thanks to Dr. Paulo Araya (Department of Chemical Engineering, Universidad de Chile) and Dr. Trevor Drage (Department of Chemical and Environment Engineering, University of Nottingham) for their valuable contributions to this study.

This research was supported partially by the National Commission for Scientific and Technological Research (Comisión Nacional de Investigación Científica y Tecnológica, CONICYT) of the Chilean Government via a doctoral scholarship awarded to Sebastián Lira-Zúñiga (No.21100358) and Leonardo Rodríguez-Córdova (No. 21090472).


REFERENCES

ACAA. 2012. Coal Combustion Products Survey. [online] <https://www.acaa-usa.org/Portals/9/Files/PDFs/revisedFINAL2012CCPSurveyReport.pdf> [november 112013]         [ Links ].

Amaya, J.T.A.; Sánchez, F. 2006. Employing fly ash and FCC catalyser waste in recovering chrome (III) from liquid effluent emitted by tanneries. Ingeniería e Investigación 25(57):39-48.         [ Links ]

Arenillas, A.; Smith, K.M.; Drage, T.C.; Snape, C.E. 2005. CO2 capture using some fly ash-derived carbon materials. Fuel 84(17):2204-2210.         [ Links ]

Barrett, E.; Joyner, L.; Halenda, P. 1951. The determination of pore volume and area distributions in porous substances. I. Computations from nitrogen isotherms. Journal of the American Chemical Society 73(1):373-380.         [ Links ]

Boumediene, M.; Benaïssa, H.; George, B.; Molina, S.; Merlin, A. 2015. Characterization of two cellulosic waste materials (orange and almond peels) and their use for the removal of methylene blue from aqueous solutions. Maderas. Ciencia y tecnología 17(1):69-84.         [ Links ]

Brunauer, S.; Emmett, P.; Teller, E. 1938. Adsorption of gases in multimolecular layers. Journal of the American Chemical Society 60(2):309-319.         [ Links ]

Castañeda, J. 2012. Estudio de las propiedades de trasporte en materiales porosos mediante espectroscopía infrarrojo con trasformada de fourier (FTIR). Tesis de magister en ciencias Facultad de Ciencias, Escuela de Química. Universidad Nacional de Colombia. Medellin        [ Links ]

Chen-Hsiu, Y.; Chih-Hung, H.; Chung-Sung, T. 2012. A Review of CO2 Capture by Absorption and Adsorption. Aerosol and Air Quality Research 12:745-769.         [ Links ]

Da Gama, C.; Navarro-Torres, V.; Falcao-Neves, A. 2010. Techological innovations on underground coal gasification and CO2 sequestration. DYNA 77:101-108.         [ Links ]

ECOBA. 2007. Coala Combustion Product. Production and Survey. 2013.[online] <http://www.ecoba.com/evjm,media/EUROCOALASH/01_Feuerborn.pdf.> [11 november 2013]         [ Links ].

Gerdemann, S. J.; O'Connor, W. K.; Dahlin, D.C.; Penner, L.R.; Rush, H. 2007. Ex Situ Aqueous Mineral Carbonation. Environmental Science & Technology 41(7):2587-2593.         [ Links ]

Hong, J.K.; Jo, H.Y.; Yun, S.T. 2009. Coal fly ash and synthetic coal fly ash aggregates as reactive media to remove zinc from aqueous solutions. Journal of Hazardous Materials 164(1):235-246.         [ Links ]

Hoyos-Barreto, A. E.; Jiménez-Correa, M.; Ortiz-Muñoz, M.A.; Montes de Correa, C. 2008. Tecnologías para la reducción de emisiones de gases contaminantes en plantas cementeras. Ingeniería e Investigación 28:41-46.         [ Links ]

Lopez-Anton, M.A.; Perry, R.; Abad-Valle, P.; Díaz-Somoano, M.; Martínez-Tarazona, M.R.; Maroto-Valer, M.M. 2011. Speciation of mercury in fly ashes by temperature programmed decomposition. Fuel Processing Technology 92(3):707-711.         [ Links ]

Malik, A.; Thapliyal, A. 2009. Eco-friendly Fly Ash Utilization: Potential for Land Application. Critical Reviews in Environmental Science and Technology 39(4):333-366.         [ Links ]

Maroto-Valer, M.; Lu, Z.; Zhang, Y.; Tang, Z. 2008. Sorbents for CO2 capture from high carbon fly ashes. Waste Management 28(11):2320-2328.         [ Links ]

Maroto-Valer, M.M.; Tang, Z.; Zhang, Y. 2005. CO2 capture by activated and impregnated anthracites. Fuel Processing Technology 86(14-15):1487-1502.         [ Links ]

Pevida, C.; Plaza, M.G.; Arias, B.; Fermoso, J.; Rubiera, F.; Pis, J.J. 2008. Surface modification of activated carbons for CO2 capture. Applied Surface Science 254(22):7165-7172.         [ Links ]

Ríos, C.A.; Williams, C.D.; Roberts, C.L. 2009. A comparative study of two methods for the synthesis of fly ash-based sodium and potassium type zeolites. Fuel 88(8):1403-1416.         [ Links ]

Sanz, A. 2012. Diseño de ciclos PSA para la captura de gases de combustión con adsorbentes comerciales. Tesis Doctoral. Departamento de Ingeniería Química. Universidad Complutense de Madrid. Madrid.         [ Links ]

Sayari, A. 2010. Stabilization of Amine-Containing CO2 Adsorbents: Dramatic Effect of Water Vapor. Journal of the American Chemical Society 132(18):6312-6314.         [ Links ]

Torres-Fuchslocher, C.; Varas-Concha, F. 2015. Desing and efficiency of a small-sacale woochip furnace. Maderas. Ciencia y Tecnología 17(2):355-364.         [ Links ]

Vassilev, S.V. 2005. Methods for Characterization of Composition of Fly Ashes from Coal-Fired Power Stations: A Critical Overview. Energy & Fuels 19(3):1084-1098.         [ Links ]

Wilcox, J. 2012. Carbon Capture. New York, Springer.         [ Links ]

Xu, X.; Song, C.; Andresen, J.M.; Miller, B.G.; Scaroni, A.W. 2002. Novel Polyethylenimine-Modified Mesoporous Molecular Sieve of MCM-41 Type as High-Capacity Adsorbent for CO2 Capture. Energy & Fuels 16(6):1463-1469.         [ Links ]

Yong, Z.; Mata, V.; Rodrigues, A.R.E. 2002. Adsorption of carbon dioxide at high temperature a review. Separation and Purification Technology 26(2-3):195-205.         [ Links ]

Yue, M.B.; Chun, Y.; Cao, Y.; Dong, X.; Zhu, J.H. 2006. CO2 Capture by As-Prepared SBA-15 with an Occluded Organic Template. Advanced Functional Materials 16(13):1717-1722.         [ Links ]


Corresponding author: snlira@uc.cl

Received: 03.12.2015 Accepted: 16.07.2016

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons